Here's some suggested language if the vehicle is of the type that it has no title (consult your own attorney - no legal advice intended):
BILL OF SALE
KNOW ALL PERSONS BY THESE PRESENTS, that for one dollar and other good and valuable consideration, receipt of which is hereby acknowledged, the undersigned __________________________ ("seller"), does hereby grant, bargain, sell, transfer and deliver to _______________________________ ("grantee"), an individual, his heirs, executors, successors and assigns, the following described [trailer] [motor vehicle], to-wit:
[description]
And the said seller hereby covenants to and with the said grantee that the seller is the true and lawful owner of the above-described vehicle; that the seller has good right to sell the same free of all claims and liens.
IN WITNESS WHEREOF, the undersigned has hereunto set his hand this ___ day of __________, 200___.
___________________________
seller
Sworn before me a Notary Public in and for the county and state set forth below:
__________________________
Notary
[get photocopy of seller’s driver’s license]